Seat erecting/folding structure for movable spectators&#39; stand

ABSTRACT

A chair-raising and folding construction is simple in construction and reduced in weight, and is also capable of, when using a moving stand with lower stages of decks protracted, effectively preventing spectators, etc. from entering into non-used decks protracted. The moving stand telescopically accommodates and protracts a plurality stages of decks ( 1,2 ). Each of the decks ( 1,2 ) has a plurality of raisable and foldable chairs ( 3 ). A leg portion ( 5 ) of the chair ( 3 ) is hinge-connected to a base frame ( 4 ) disposed on the deck ( 1 ). A crank member ( 10 ), comprising a swing arm ( 12 ) protruding upward from the base frame ( 4 ), and a hook ( 13 ) protruding forward from a lower end portion of the swing arm ( 12 ), is rotatably supported at a corner portion thereof. The swing arm  12  has such a protruding length such that a distal end portion thereof abuts against a front end surface ( 2   a ) of the upper stage-side deck ( 2 ). The leg portion ( 5 ) is provided with a lock member ( 9 ) engaged with the hook when the leg portion takes the raised attitude.

TECHNICAL FIELD

The present invention relates to chair-raising and folding constructionsfor moving stands which are applied to not only indoor facilities suchas gymnasiums, lecture halls, and multi-purpose halls, but also indooror outdoor athletic facilities, and public halls, etc. This moving standis substantially of a telescopic construction as a whole and soconstructed such that a plurality of stages of decks are protractedstep-wise on occasion demands, and the decks can be, after use,accommodated while being arranged in an up-and-down directions. In thischair-raising and folding constructions, only folding operation of aplurality of chairs, which are arranged continuously to one another orindependently on each of the decks, is automated.

BACKGROUND ART

Conventionally, various kinds of moving stands, which can telescopicallyaccommodate and protract a plurality of stages of decks horizontallyarranged, have been proposed. They are, in most cases, capable ofproviding a plurality of chairs on each of the decks, thereby enabling apredetermined number of spectators, etc. to sit on the moving stand.

Then, in such a moving stand, accommodating the respective decks whenthey are unused requires causing each of the chairs to take the foldedattitude forward, which requires causing each of the chairs to take theraised attitude, enabling the spectators to sit thereon, when the movingstand is used.

Therefore, as described in JP-A-62-201109, the applicant has proposed anautomatic chair-raising and folding apparatus which is capable ofautomatically raising and folding chairs without using special powersources, with the protracting and accommodating operation of decks.

In this apparatus, a main part of which is shown in a side view of FIG.1, a bed frame 103 is disposed on a deck 101, and a chair leg 105 isarranged on the bed frame 103 raisably and foldably. A three-prongedlock ring 111 has a locking and unlocking roller 107 as a weight, and ahook portion 109 at a lower pronged portion thereof. The leg 105 isconnected with the three-pronged lock ring 111 with a front endpenetrating shaft 113 as a fulcrum in such a manner that the roller 107can move downward. Disposed on a back side of the leg 105 is a lockingangle 115 for holding the leg 105 in the raised state due to theengagement with the hook portion 109 of the lock ring 111 with theroller 107 moving downward; therefore, when the deck 101 is retreated,the roller 107 abuts against the upper stage-side deck 117, therebycausing the hook portion 109 and the locking angle 115 to be releasedand disengaged from each other. As a result, protracting each of thedecks causes the chairs to be automatically raised, and accommodatingeach of the decks causes the chairs to be automatically folded forward.

The proposed technique has, however, disadvantages that the constructionof the apparatus becomes complicated, and further the weight of theapparatus, in its turn the weight of each stage of the decks isincreased.

Also, when the moving stage is used with only intermediate stages of thedecks, i.e. the lowest two stages of the decks out of six stages of thedecks protracted, suitably seating on the chairs of the second deck,i.e. raising up backrests of the chairs, disposed on the second deck,above a passage B of the third deck A requires causing the third deck Aalso to take the protracted attitude. According to the proposedtechnique, protracting the third deck A causes the chairs disposed onthe deck to necessarily take the raised attitude; therefore, there is adisadvantage, from the viewpoint of spectator-guide-countermeasure, thatthe spectators, etc. are required to be prevented from entering into thepassage B by taking a suitable countermeasure of surely preventing thespectators from using the chairs C, e.g. roping off, or fencing in theplace, or guiding the spectators, etc. by guides, guards, etc.

Moreover, in such a case, when the chairs C on the third deck A are freeto be used, the backrests of the chairs C interfere with the upperstage-side accommodating deck above the deck A, thereby disabling thebackrests to be sufficiently folded rearward, which disables the seat totake a satisfactory free attitude. Therefore, not only the comparabilityto sit on becomes bad, but also unexpected forces act on the chairs C,which possibly may cause the chairs C to get out of order, etc.

Also, in the proposed technique, automatic raising and reversingapparatuses are independently arranged for respective chairs on the samedeck. For example, as exemplified in FIG. 3, so long as the first stagedeck D retreats during the protracted decks are accommodated while beinginclined in the fore and rear direction, i.e. in the advancing andretreating direction, under the influence of the condition, such asunevenness of the floor on which the moving stand is disposed, and soon, even when the chairs disposed on one end portion of the deck D inthe longitudinal direction, in its turn the leg 105 of the chair isunlocked, and hence the leg 105 starts to fold, the legs 105 of theother chairs may be still in the locked condition. Especially when aplurality of chairs disposed on the deck D are so-called connectedchairs which are connected to one another, the occurrence of theabove-mentioned state provides a problem that the connected chairsundergo an unexpected large torsional external force, etc. not onlythereby causing the connected chairs to be damaged worst of all, butalso thereby causing the deck D to be retreated to disable the otherchairs to be smoothly unlocked. The same is true of the advancing andretreating direction-wise inclination of the deck when the specifieddeck is advanced to thereby be protracted.

The present invention has been made as a result of investigating thesubject of solving the above-mentioned problem included in the aboveproposed technique. It is therefore an object of the present inventionto provide a chair-raising and folding construction for a moving stand,which is capable of precluding the possibility of increasing the weightof decks, and effectively preventing spectators, etc. for entering intoa surplus stage of decks which are, when lower decks are protracted foruse, obliged to be protracted to a rear side of the lower decks, and toprovide a chair-raising and folding construction for a moving stand,which is capable of, even if a plurality of chairs disposed on the deckare connected to one another, not only raising but also folding smoothlyand surely the connected chairs irrespective of the retracted attitudeof the deck, and also of satisfactorily preventing the connected chartsfrom receiving a torsional force, etc.

DISCLOSURE OF THE INVENTION

The present invention provides a chair-raising and folding constructionfor a moving stand, which is capable of substantially telescopicallyaccommodating and protracting a plurality stages of horizontal decksarranged at spaces in up-and-down directions, each of the decks having aplurality of chairs thereon raisably and foldably, wherein a leg portionof the chair is hinge-connected foldably forward to a base framedisposed on the deck, a crank member, comprising a swing arm protrudingupward from the base frame, and a hook protruding forward from a lowerend portion of the swing arm, is rotatably supported on a rear portionof the leg portion at a corner portion thereof, the swing arm has such aprotruding length as that a distal end portion thereof abuts against afront end surface of the upper stage-side deck, and the leg portion isprovided with a lock member engaged with the hook when the leg portiontakes the raised attitude.

According to this raising and folding construction, the construction asa whole becomes simple, and the total weight is reduced. Also, in thisconstruction, when a desired number of stages of decks are retracted,the connected chairs or the respective independent chairs disposed oneach of the decks, which takes the folded attitude, are raised by theworkers, thereby causing the lock member disposed on the leg portion ofthe chair to be engaged to the hook disposed on the crank member, whichenables the chair to surely take the raised attitude.

On the other hand, the chair taking the raised attitude is folded bycausing the front end surface of the upper stage-side deck to abut, whenretracting or accommodating the decks, against the swing arm of thecrank member disposed on the deck to thereby swing the swing armforward, which enables the hook and the lock member of the leg portionto be disengaged from each other. This enables the chairs to beautomatically folded with the accommodation of the decks.

According to such a raising and folding construction, when using thelower decks, in its turn the chairs disposed on the decks, as is thecase with those above mentioned, the chairs disposed on a surplus stageof the decks which is obliged to be protracted can be maintained in thefolded state, thereby not only preventing the spectators, etc. fromsitting on the chairs disposed on the surplus stage of the decks, butalso effectively preventing the spectators, etc. from unexpectedlyentering into the surplus state of the decks without disposing specialentering-restricting means, stationing guides, etc.

In such a chair-raising and folding construction, more specifically,shafts of rotatably supporting the crank members to the base frames areconstructed as a common shaft of all the crank members arranged on thesame deck. This enables the action of one of the crank members, in itsturn its swing arm to be transmitted to all the crank members.

As a result, so long as the hook and the lock member of the leg portionare, when the swing arm and the front end surface of the upperstage-side deck are abutted against each other, disengaged from eachother in one of the crank member even if one stage or plural stages ofthe decks are, especially when the decks are accommodated, retreatedwhile being inclined in the protracting and retracting direction, theaction of the common shaft causes all the crank members disposed on thesame deck to be unlocked, thereby causing all the chairs to start tosmoothly fold. This, even if the chairs disposed on the deck areconnected to one another, prevents the connected chairs from receivingan unexpected external force, such as a torsional external force,thereby enabling the chairs to be smoothly and surely folded without thepossibility of damaging the chairs, etc.

Still preferably, this chair-raising and folding construction furthercomprises leg portion spring means for urging the leg portion of thechair in the raising direction, and a stopper for preventing the legportion from being inclined rearward.

This leg portion spring means functions to assist the manual raisingoperation of the chairs. Also, the stopper functions to prevent, whenthe chairs are locked in the raised condition, the chairs from beingdisplaced more rearward to stabilize its raised attitude.

Further preferably, there are provided auxiliary spring means, such asan extension spring, a compression spring, a torsion spring, etc., forurging the swing arm rearward, and positioning means for restricting therearward inclined position of the swing arm. Accordingly, each of theauxiliary means and the positioning member is capable of returning thecrank member in such arm-raised attitude as that the swing arm abutsagainst the positioning member, and further of automatically and surelylocking the chair to the raised position without the manual work underthe action of the auxiliary spring means.

Still preferably, the leg portion of the chair and the crank member areconnected to each other by a link member, such as a pressing or tensilelink member, forcing the swing arm to be folded forward with the foldedmovement of the leg portion, and the construction comprises auxiliaryspring means, such as an extension spring, a compression spring, atorsion spring, etc., for urging the swing arm rearward.

Accordingly, the action of the auxiliary spring means for urging theswing arm rearward causes the lock member of the leg portion and thehook of the crank member to be surely engaged to each other when the legportion is raised. On the other hand, abutment between the distal end ofthe swing arm and the front end surface of the upper stage-side deckcauses the above-mentioned engagement to be released, thereby enablingthe leg portion, in its turn the chair to be folded forward, as is thecase with those above mentioned.

Then, on this occasion, when the chair is thus folded, the link memberfunctions to cause the arm to be folded forward against the spring forceof the auxiliary means, and then the swing arm is maintained in thefolded state even when it is accommodated below the upper stage-sidedeck, which eliminates the need for arm guide means arranged on the backsurface of the upper stage-side deck at a plurality of locations in thelongitudinal direction of the deck, or the lateral direction of thestand, for preventing the distal end of the swing arm from abuttingagainst the main body of the upper stage-side deck when the upper sidedeck is contacted to the distal end of the swing arm to be advanced, asis the case in which the swing arm is maintained in the raised attitudeeven when the leg portion is in the folded state. This reduces theweight and the cost of the deck, and further eliminates the need for thedesign man-hours required to determine the arrangement of the arm guidemeans, etc.

Further preferably, there are provided one kind of so-called over centertype spring means, such as a pressing or tensile spring, for urging theswing arm in a forward and a rearward direction with thefolding-displacement and the raising-displacement of the leg portion,respectively, and positioning means for restricting the rearwardinclined position of the swing arm.

Accordingly, when the leg portion is folded or raised, the action of theover center type spring means causes the swing arm to undergo a clickmovement, thereby enabling the swing arm to be, as is the case withthose above mentioned, maintained in the folded attitude forward duringthe time the leg portion is folded, which provides the same effect asthose above mentioned. Furthermore, there is no need for providing theauxiliary spring means for urging the swing arm rearward.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 are side views of a main portion of a prior art;

FIG. 2 is a side view showing a state in which lower stages of decks areprotracted;

FIG. 3 is a schematic plan view showing a state in which a deck isretracted in an inclined condition;

FIG. 4 is a partially sectional side view of an embodiment of thepresent invention;

FIGS. 5 are enlarged views of a main part of the embodiment shown inFIG. 4;

FIGS. 6 are side views showing modes in which a chair is raised;

FIG. 7 is a side view showing a state in which lower stages of decks areprotracted;

FIGS. 8 are side views showing modes in which the chair is folded;

FIG. 9 is a schematic plan view showing a state in which a deck isretracted in an inclined condition;

FIGS. 10 are views showing another embodiment of the present invention;

FIGS. 11 are views useful in explaining an operation of the constructionshown in FIGS. 10;

FIGS. 12 are views useful in explaining, in contradistinction to eachother, states in which a swinging arm is changed in attitude;

FIGS. 13 are sectional side views of a main part of another embodimentof the present invention;

FIGS. 14 are sectional side views of a main part of still anotherembodiment of the present invention; and

FIGS. 15 are sectional side views of a main part of further anotherembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 4 is a partially sectional side view showing an embodiment of thepresent invention in association with a specified deck. In FIG. 4,reference numeral 1 designates a lower stage-side deck arranged in thehorizontal attitude, and 2 an upper side deck arranged in the horizontalattitude also, while the decks 1 and 2 taking the protracted attitude.

Frames 4 are arranged on a rear end portion of each of the decks, i.e.the lower stage-side deck 1 in FIG. 4 so as to be positionedcorresponding to chairs 3, respectively, and leg portions 5 of thechairs 3 is hinge-connected to the base frames 4, respectively, therebyenabling the leg portions 5, in its turn the chairs 3 to be rotatedbetween the raised position shown by the actual line in FIG. 4 and theforward folded position shown by the imaginary line in FIG. 4.

Preferably, leg portion spring means, e.g. a coil spring 7 for urgingthe leg portion 5 in the raised direction is connected to the legportion 5 and the base frame 4, respectively. Also, to prevent the legportion 5 from excessively rotating rearward to sufficiently stabilizethe raised attitude of the leg portion 5 and the chair 3, a stopper,e.g. a bolt 8 is, as shown in FIGS. 5(a) and 5(b), attached to the baseframe 4 so as to protrude toward the leg portion, and a lock member,e.g. a horizontal rod 9 is fixed or secured to the leg portion 5,thereby enabling the horizontal rod 9 to abut against a front surface ofthe bolt 8, with the leg portion 5 taking the right raised attitude.

Further, a corner portion of a crank member 10 is rotatably supported,through a shaft 11, on a rear portion of the base frame 4 with respectto a hinge-connection position of the leg portion 5. Preferably, theshaft 11 is penetrated through all the crank members on the same deck asa common shaft. Moreover, this common shaft may not be a single shaftcontinuous over the whole length, and may consist of a plurality ofshaft members connected to one another.

Then, each of the crank members 10 is provided with a swing arm 12protruding from the base frame 4, and a hook 13 protruding from a lowerend portion of the swing arm 12 forward, i.e. on a side of the legportion, thereby enabling the hook 13 to be engaged with the horizontalrod 9 of the leg 5 which is in the raised attitude. On this occasion,the swing arm 12 has an upward protruding length as that its distal endportion abuts, as apparent from FIG. 4, against a front end surface 2 aof the upper stage-side deck 2 when the hook 3 is engaged with thehorizontal rood 9. More preferably, the distal end portion is rotatablyattached with a roller 14, thereby decreasing a friction force betweenthe swing arm 12 and the upper stage-side deck 2.

Also preferably, connected to such a crank member 10 is one end ofauxiliary spring means, e.g. an extension coil spring 15 for urging theswing arm 12 rearward, and the other end of the coil spring 15 isconnected to the base frame 4. On the other hand, a rearward swing limitposition of the swing arm 12 is specified by a notch end face 4 b, as apositioning means, which is formed on a top wall 4 a of the base frame4, as shown in a perspective view of FIG. 5.

In thus constructed raising and folding apparatus, when the specifieddeck is protracted, the chair 3 on the deck 1 is in the folded state asexemplified in FIG. 6(a), the crank member 10 is in the rearward swinglimit position at which the swing arm 12 abuts against the notch endsurface 4 b due to the action of the extension coil spring 15.Accordingly, the above-mentioned chair 3 is raised by rotating the chair3 on the required deck in the raised direction by means of the manualwork of the worker as exemplified in FIG. 6(b) to thereby engage thehorizontal rod 9 of the chair leg portion 5 with the hook 13 of thecrank member 10 positioned at the rearward swing limit position.

To this end, when protracting intermediate stages of the decks out of aplurality of stages of the decks, e.g. the lowest two stages of thedecks 21, 22 out of six stages of the decks in the example in FIG. 7 tothereby cause the spectators, etc. to sit thereon, all the chairs 3 canbe maintained in the folded state for the third stage of the deck 23,which is obliged to be protracted only for spectators to properly sit onthe chairs 3 on the second stage of the deck 22. This sufficientlyprevents the spectators, etc. from entering into the third stage of thedeck 3 and sitting on the chair 3 of the deck without disposing meansfor restricting entering into the third stage deck 23, stationingguides, etc.

On the other hand, after the use of the moving stand has been finished,the respective decks are retracted in the ascending order from thelowest stage-side with the chairs 3 maintained in the raised state,thereby causing the decks to be accommodated with the respective chairs3 automatically folded forward.

On this occasion, the chairs 3 are, according to the decks'retracting-displacement, automatically folded as follows:

First, as shown in FIG. 8(a), the swing arm 12 of the crank member 10,in its turn the roller 14 disposed thereon abuts against the front endsurface 2 a of the upper stage-side deck 2, thereby causing the swingarm 12, in its turns the hook 13 to swing, as shown in FIG. 8(b) aroundthe rotatably supporting shaft, preferably together with shaft 11, whichcauses the horizontal rod 9 of the leg portion to be separated from thehook 13. This allows the leg portion 5 of the chair 3 to rotate aroundthe pin 6 in the folded direction; thereafter, the upper stage-side deck2 causes the swing arm 12 to further swing when the deck 1 iscontinuously retracted, which causes the leg portion 5 to be, as shownin FIG. 8(c), rotated or folded against the spring force of the coilspring 7 through the roller 14.

Then, such a rotation or folding of the leg portion 5 causes the chair 3including the leg portion 5 to move in position of the center of gravityin the folded direction. When the chair 3 is folded against the springforce of the coil spring 7 without the action of the external force, itis folded, while undergoing the cushion action of the coil spring 7, ata speed higher than the swing speed of the swing arm 12, therebyresulting in the perfectly folded state in which the back surface of theseat plate is supported by the deck 1, as shown in FIG. 8(d).

As a result, the subsequent retracting-displacement of the deck 1 iscarried out for only the purpose of accommodating the deck 1.

Then, although the chair 3 is thus folded, in a case where the rotatablysupporting shaft 11 is arranged commonly to all the crank members on thesame deck, and also fixed or secured to all the crank members, the legportion of the chair being unlocked in any one of the crank memberscauses all the crank members to be simultaneously unlocked. Therefore,as shown in, e.g. the schematic plan view of FIG. 9, even if thespecified deck 21 is retracted with its attitude inclined in thelongitudinal direction when the decks are accommodated, theswinging-displacement of the crank member 10 which is first disengagedwith the horizontal rod 9 of the leg portion 5, the right end one in thedrawings, causes all the other crank members 10 to be unlocked.

Therefore, even if a plurality of the chairs disposed on the same deckare connected to one another, and the deck takes the rearward retractedattitude shown in FIG. 9 when they are accommodated, no connected chairsundergo a torsional external force and other external forces, therebyresulting in a permanently smooth and sure folding operation.

FIG. 10 is a view showing another embodiment of the present invention.This embodiment is different from that of FIG. 5 in that a portion ofthe raised leg portion 5 below the hinge pin 6 is connected through apressing link member 31 to a portion of the corner portion of the crankportion 10 opposite to the hook 13 with respect to the rotatablysupporting shaft 11.

The pressing link member 31 shown in the drawings is shaped like aslightly curve protruding downward in order to prevent interference withthe pin 6 and the shaft 11, and also has, e.g. an oblong hole, at aportion thereof connected to the crank member 10, for allowing the crankmember 10 to slightly swing around the shaft 11 in order to ensure thehook 13 engaging to and disengaging from the horizontal rod 9.

In this embodiment, the extension coil spring 15 as auxiliary springmeans for urging the swing arm 12 rearward is bridged between respectiveconnecting pings of the pressing link member 31, thereby decreasing arequired extending amount of the extension coil spring 15 compared withthat of the above-mentioned embodiment.

According to thus constructed raising and folding construction, e.g.when retraction of the lower stage-side deck causes the distal end ofthe swing arm 12 to abut, as shown by the imaginary line in FIG. 11(a),against the front end surface 2 a of the upper stage-side deck 2, theswing arm 12 is rotated within a range of the length of the oblong holddisposed on the link member 31, thereby causing the hook 13, for holdingthe leg portion 5 in the raised state as shown in FIG. 10(b), to beseparated from the horizontal rod 9. Therefore, when the lowerstage-side deck is further retraced, the swing arm 12 presses the legportion 5, thereby causing the leg portion 5 to be folded as is the casewith FIG. 8, which causes the leg portion 5 to be, as shown in FIG.11(b), perfectly folded on the lower stage-side deck.

Then, according to this raising and folding construction, when the legportion 5 is thus folded, the pressing link member 31 presses a portionthereof connected to the crank member 10 against the spring force of thetension spring force 15, thereby causing the swing arm 12 also to be, asthe leg portion 5 is folded, gradually folded in the same direction,which causes the swing arm 12 to be, when the led portion 5 takes thefolded attitude, maintained in the folded state as shown in FIG. 11(b).

Therefore, when the lower stage-side deck is entered into just below theupper stage-side deck with the leg portion 5, in its turn the chair 3perfectly folded, the distal end of the swing arm 12 is positioned, asshown in FIG. 12(a), so as to be sufficiently separated from the backsurface of the upper stage-side deck 2; therefore, protracting the lowerstage-side deck 1 toward the upper stage-side deck 2 may not cause thedistal end of the swing arm 12 to abut against the back surface of theupper stage-side deck 2.

On the other hand, according to the above-mentioned raising and foldingconstruction shown in FIG. 4, etc., the swing arm 12 takes, also whenthe leg portion 5 and the chair 3 are perfectly folded, the raisingattitude shown in FIGS. 6(a), 8(d), etc., or the rearward inclinedattitude. In such a case, as shown in FIG. 12(b), attaching arm guidemeans, e.g. a guide rod 32, positioned corresponding to the swing arm12, to the back surface of the upper stage-side deck 2 so as to extentin the longitudinal direction of the deck substantially eliminates theunevenness of the back surface of the deck, and hence, when the lowerstage-side deck is entered into below the upper stage-side deck togetherwith the chairs, etc. and protracted from below the upper stage-sidedeck, the guide rod 32 guides the movement of the distal end of theswing arm, which requires preventing the swing arm from unexpectedlyabutting against the back surface of the deck.

Therefore, the construction shown in FIG. 10 eliminates, compared withthe above case, the need for the design man-hours of determining theattaching position of the guide rod 32 and the man-hours of attachingthe guide rod 32, and hence effectively reduces the weight of the deck,the cost, etc.

Then, in the construction shown in FIG. 10, the leg portion 5 is raisedby a worker applying an upward external force to the leg portion 5taking the attitude shown in FIG. 11(b) to thereby rotate it,functioning the link member 31 as an tension member in this case tothereby displace the swing arm 12 together with the leg portion 5 in theraising direction, finally engaging the horizontal rod 9 to the hook 13with leg portion 5 taking the perfect raised attitude shown in FIG.10(b).

FIG. 13 is a sectional side view of a main part of another embodiment.The link member is comprised of an tension link member 33, one end ofwhich is connected to a portion of the leg portion 5, which is slightlyabove the pin 6 when the leg portion 5 takes the raised attitude, andthe other end is connected to a portion of the crank member 10, which ison a side of the swing arm with respect to the rotatably supportingshaft 11. Then, the extension coil spring 15 is connected to the cornerportion of the crank member 10 and the best frame 4, respectively.

According to thus constructed raising and folding construction, the legportion 5, which is in the perfect raised state as shown in FIG. 13(a),is folded by causing the distal end of the swing arm 12 to abut againstthe upper stage-side deck 2 as shown in FIG. 13(b), to thereby rotatethe swing arm 12, preferably together with the rotatably supportingshaft 11, thereby causing the hook 13 to be separated from thehorizontal rod 9, and continuously pressing the leg portion 5 throughthe swing arm 12. Such folding-displacement of the leg portion 5 causesthe tension link member 33 to undergo a tension force, thereby causingthe swing arm 12 to be folded in the same direction, which causes theswing arm 12 also to be maintained in the folded attitude when the legportion 5 takes the perfect folded attitude as shown in FIG. 13(c).

Therefore, using this construction also sufficiently eliminates a fearthat the distal end of the swing arm 12 abuts against the unevenness ofthe back surface of the upper stage-side deck 2, etc. without requiringapplying special arm guide means to the back surface.

Also, according to this construction, the leg portion 5 is raised byrotating the swing arm 12 also in the raising direction using thepressing function of the link member 33 exhibited when the leg portion 5is rotated in the raised direction, and finally engaging the horizontalrod 9 to the hook 13 as shown in FIG. 13(a).

FIG. 14 is a sectional side view of a main part of still anotherembodiment. In FIG. 14, a compression spring 34 as one example of springmeans is connected, at one end thereof, to the corner portion of thecrank member 10 opposite to the hook 13 and the swing arm 12 withrespect to the rotatably supporting shaft 11 of the crank member 10, andconnected to the base frame 4 at the other end thereof, which makes thespring 34 a so-called over center type of functioning as a compressionspring even when a center line of the spring 14 is positioned at eithersides of a center of the shaft 11 according to the rotation-displacementof the crank member 10. This causes the swing arm 12 to undergo a clickmovement in the raising direction and the folding direction.

Moreover, this construction is provided with positioning means, e.g. thenotch end surface 4 b of the base frame top wall 4 a, described usingFIG. 5(c), for restricting the rearward inclination position of theswing arm 12 in order to prevent the swing arm 12 from being excessivelydisplaced in the raised direction. On the other hand, the raiseddirection-wise movement of the swing arm 12 is defined by abutment ofthe swing arm 12 or the crank member 10 to the leg portion 5, whicheliminates the need for providing special positioning means.

According to such a raising and folding construction, when the legportion 5 takes the raised attitude, the compression spring 14 exertsthe clockwise force to the crank member 10 as shown in FIG. 14(a),thereby strengthening the engagement between the hook 13 and thehorizontal rod 9.

On this occasion, the leg portion 5 is folded as is the case with eachof the above mentioned embodiments, the rotational movement of the swingarm 12 based on abutment of the swing arm 12 to the upper stage-sidedeck causes the hook 13 to be separated from the horizontal rod 9, andthen the leg portion 5 to be folded, as shown in FIG. 14(b).

In this case, the compression spring 34 is displaced in a directionopposite to that of the shaft 11 while being slightlycompression-deformed in itself, thereby causing the swing arm 12 to be,when the leg portion 5 takes the perfect folded attitude shown in FIG.14(b), urged in the raised direction.

As a result, this raising and folding construction also is capable ofsufficiently eliminating a fear that the distal end of the swing arm 12abuts against the back surface of the upper stage-side deck, etc.without providing special arm guide means on the back surface of theupper stage-side deck.

FIG. 15 shows a case in which an extension spring 35 is used as thespring means. In this case, the point of application of force of theextension spring 35 is arranged on the crank member 10 at a side of thehook 13 and the swing arm 12 with respect to the rotatably supportingshaft 11 of the crank member 10, and also an escape piece 36 isinterposed between the extension spring 35 and the point of applicationof force in order to prevent interference between the rotatablysupporting shaft 11 and the extension spring 35.

The above-mentioned spring 35 also functions as the so-called overcenter type spring as is the case with the above-mentioned compressionspring 34, thereby causing the swing arm 12 to undergo a click movement.Also, selection of the point of application of force increases theengagement force between the hook and the horizontal rod 9 when the legportion 5 takes the raised attitude as shown in FIG. 15(a), andmaintains the swing arm 12 in the folded state when leg portion 5 takesthe folded attitude as shown in FIG. 15(b).

As a result, this construction provides the same operation and effect asFIG. 14.

INDUSTRIAL APPLICABILITY

As apparent from the descriptions above, the present invention providesa chair-raising and folding construction for a moving stand which issimple in construction, and reduced in weight and occupied space, andwhich is capable of, when using the moving stand with lower stages ofdecks protracted, effectively preventing spectators, etc. from enteringinto non-used decks protracted.

In particular, it is possible, when the chairs on the decks areconnected to one another, to smoothly and surely fold the chairsirrespective of the retracted attitude of the deck, thereby sufficientlypreventing the chairs from receiving an unexpected force such as atorsional force, etc.

What is claimed is:
 1. A chair-raising and folding construction for a moving stand, which is capable of substantially and telescopically accommodating and protracting a plurality of horizontal decks arranged at spaces in a vertical direction, each of said decks having a plurality of raised and foldable chairs, said construction comprising: a leg portion of said chair that is hingedly connected in a foldably forward direction to a base frame disposed on said deck; and a crank member comprising a swing arm protruding upwardly from said base frame and a hook protruding forwardly from a lower end portion of said swing arm, a corner portion of said crank member being rotatably supported on a rear portion of said base frame, said swing arm has such a protruding length so that a distal end portion thereof abuts against a front end surface of the upper stage-side deck, and said leg portion is provided with a lock member engaged with said hook when said leg portion is raised upwardly in the vertical direction.
 2. A chair-raising and folding construction for a moving stand, as claimed in claim 1, wherein shafts for rotatably supporting said crank members to said base frames are constructed as a common shaft of all said crank members arranged on the same deck.
 3. A chair-raising and folding construction for a moving stand, as claimed in claim 1, further comprising leg portion spring means for urging said leg portion in the raising direction, and a stopper for preventing said leg portion from being inclined rearward.
 4. A chair-raising and folding construction for a moving stand, as claimed in claim 1, further comprising auxiliary spring means for urging said swing arm rearward, and positioning means for restricting the rearward inclined position of said swing arm.
 5. A chair-raising and folding construction for a moving stand, as claimed in claim 1, wherein said leg portion and said crank member are connected to each other by a link member forcing said swing arm to be folded forward with folded movement of said leg portion, and said construction comprises auxiliary spring means for urging said swing arm rearward.
 6. A chair-raising and folding construction for a moving stand, as claimed in claim 5, wherein said link member comprises one of a pressing link member and a tensile link member.
 7. A chair-raising and folding construction for a moving stand, as claimed in claim 1, comprising spring means for urging said swing arm in a forward and a rearward direction with the folding-displacement and the raising-displacement of said leg portion, respectively, and positioning means for restricting the rearward inclined position of said swing arm.
 8. A chair-raising and folding construction for a moving stand, as claimed in claim 7, wherein said spring means comprises one of a pressing spring and a tensile spring. 